The intermixed boundaries of tumor and normal tissues poses a major challenge in precise and complete targeting of tumor and may facilitate non-targeted effects. In such scenario, irradiated tumor cells may interact with neighbouring unirradiated tumor/normal cells and vice versa. Depending on the type of interacting partners and nature of interaction between them the final outcome of the therapy may change either in terms of tumor regression or recurrence as well as detrimental side effects. The mechanisms underlying radiation-induced signalling are complex, and neither the signals released nor the pathways of their transmission are completely understood. Emerging paradigm suggest exosomes as one of the crucial mediators of cell-cell communication post radiotherapy. This project would explore the diverse roles of exosomes in radiation-induced effects with underlying mechanism and its implications in therapy outcome.